Re: Exception handling and snarky compiler

From:
Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>
Newsgroups:
comp.lang.java.help
Date:
Wed, 27 Aug 2008 21:07:52 -0700
Message-ID:
<48b6243a$0$25543$7836cce5@newsrazor.net>
Roland de Ruiter wrote:

To get rid of the error, initialize the variable with null at its
declaration ( /*A*/ in the example code below). This is the best
solution IMO.

I disagree. More to follow.

 > Alternative 1 is assign null to the variable after the

System.exit call (). The second alternative is to put a return statement
there ( /*B*/ ).

This is a better approach, but there are better still.

public void process(String fileName) {
    RandomAccessFile file /*A*/;
    try {
        file = new RandomAccessFile(fileName, "r");
    } catch (FileNotFoundException ex) {
        System.out.println("Couldn't open " + fileName);
        System.exit(1);
        /*B*/
    }

    // Error on the line below: "The local variable
    // 'file' may not have been initialized"
    file.seek(0);

    // and other stuff
}


There are at *least* two other approaches. One is to put the "file.seek"
code within your try/catch block. The better approach is to throw an
exception from process, and let the code calling process worry about
exiting or not.

If nothing else, I would throw new AssertError("Never reaches this
point"); at position *B* above.
--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>

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